To learn more search for ‘TCB 346/T 875’ in our archives at bt.com/archives

The Post Office Tower, now the BT Tower (c.1970)

Staff poster showing the Post Office’s satellite station at Goonhilly Downs (1960s)

To learn more search for ‘TCB 420/IRP (PR) 1’ in our archives at bt.com/archives

Automatic exchange advert (1930s)

To learn more search for ‘TCB 699/1/25’ in our archives at bt.com/archives

The Post Office Tower, now the BT Tower (c. 1966)

To learn more search for ‘TCB 346/T 648’ in our archives at bt.com/archives

Wartime publicity poster (1943)

To learn more search for ‘TCB 319/PRD 310’ in our archives at bt.com/archives

‘How to dial’ notice, introducing the world’s first 999 service (1937)

To learn more search for ‘POST 33/5220’ in our archives at bt.com/archives

Publicity poster showing the London international telephone exchange (c.1938)

To learn more search for ‘TCB 319/PRD 219’ in our archives at bt.com/archives

Continental exchange in Faraday Building, London (1930s)

To learn more search for ‘TCB 539/AB 49’ in our archives at bt.com/archives

Telephonists at switchboard (c.1900)

To learn more search for ‘TCB 417/E 73373’ in our archives at bt.com/archives

Control positions in Faraday Building, London (1930s)

To learn more search for ‘TCB 475/YK/YK29’ in our archives at bt.com/archives

Advertising poster (1936)

To learn more search for ‘TCB 319/PRD 125’ in our archives at bt.com/archives